This invention relates to laryngeal masks and their manufacture.
Laryngeal mask airways are used to ventilate and provide anaesthetic gas to a patient during surgery. Laryngeal mask airways differ from endotracheal tubes, which extend into the trachea and terminate beyond the vocal folds. By contrast, laryngeal mask airways have a tube opening into the centre of a generally elliptical mask, which seals in the region of the hypopharnyx, at the top of the trachea. Laryngeal masks are described in, for example, U.S. Pat. No. 5,355,879, U.S. Pat. No. 5,305,743, U.S. Pat. No. 5,297,547, U.S. Pat. No. 5,282,464, GB 2267034, U.S. Pat. No. 5,249,571, U.S. Pat. No. 5,241,956, U.S. Pat. No. 5,303,697, GB 2317830, GB 2249959, GB 2111394, EP 448878, U.S. Pat. No. 4,995,388, GB 2205499, GB 2128561, GB 2298797, GB 2321854, GB 9900596, GB 2323289, GB 2323290, GB 2318735 and GB 2330312. Laryngeal mask airways have certain advantages over endotracheal tubes but their more complex construction makes them considerably more expensive. As a result, the majority of laryngeal mask airways are reusable devices, which are sterilized after use.